Siemens 7UT6 Differential Protection Relay

1
Siemens 7UT6Differential Protection Relay
EEPM 563

• MatLab Simulation

Aidil Azwin Zainul Abidin SE 20019 Daniel Andrew
Sen SE 20240 Azlin Aziz SE 20206 Hardanjit S
Gosal SP 20054 Jasni b. Rose SE 20144 Wong Lee
Ming Jolene SE 20207 Renuga Verayiah SE
20237 Rohayiah Mohd Shahuri SE 20241 Sairul
Izwan Safie SE 20221 Wan Noraireen Wan Md
Nor SE 20212 20 November 2005
2
The Problem

• Simulation tripping of the Siemens 7UT6
  Differential Protection Relay
• using MatLab
• for vector groups D0, D1, D5, D6, D7, and D11
• The program allows the user to input protection
  parameters, which are then used in the simulation
• Graphs showing the phase currents and voltages of
  the 3 phases are displayed upon completion of the
  simulation

3
Background

• Kirchoffs Current Law
• The sum of currents entering a node is equal to
  the sum of currents leaving the node

4
Common Practice

• A differential protection scheme would usually
  include
• The differential protection relay itself
• The Current transformers on both primary and
  secondary windings
• An interposing transformer to compensate
  difference in vector and current

5
Scope

• This paper will investigate the use of a relay
  that will eliminate the use of the interposing
  transformer (ICT).
• This is significant because
• Vector group compensation for primary and
  secondary windings can be done without changing
  the ICT.
• The calculation of stabilizing resistor, RS for
  an earth fault relay can be simplified without
  the presence of the ICT.

6
Simulink Model
7
7UT6 Relay Block Diagram
8
Vector CompensationMatrix

• A (2/3)

9
Zero Sequence Current Elimination Matrix

• B (1/3)

10
Decision (Trip Logic)

• The relay will trip as soon as it detects a fault
  in any one of the three faults.
• The future output of the relay would also depend
  on the present output.
• Once the relay outputs a 0 it continue to output
  0 to avoid the breaker from opening and closing.

11
D11 Vector Group Single phase to ground fault
12
D11 Vector Group Double phase to ground fault
13
D11 Vector Group Double phase-to-phase fault
14
D11 Vector Group Triple phase fault to ground
15
D11 Vector Group Triple phase-to-phase fault
16
D11 Vector Group Out of zone fault
17

• The End